In your excellent studies of words, what have you found on apostello and apostolos?
I ask because I think it is in the concepts around those words that we on the RC/EO sides find a tertium quid between usurping God's authority and saying the Church has no authority.
apostello to send, also pempo
But I have greater witness than [that] of John: for the works which the Father hath given me to finish, the same works that I do, bear witness of me, that the Father hath sent [apostello] me. And the Father himself, which hath sent me [pempo], hath borne witness of me. Ye have neither heard his voice at any time, nor seen his shape. And ye have not his word abiding in you: for whom he hath sent, [apostello] him ye believe not. Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me.- John 5:26-39
Judas saith unto him, not Iscariot, Lord, how is it that thou wilt manifest thyself unto us, and not unto the world? Jesus answered and said unto him, If a man love me, he will keep my words: and my Father will love him, and we will come unto him, and make our abode with him. He that loveth me not keepeth not my sayings: and the word which ye hear is not mine, but the Father's which sent [pempo] me. John 14:22-24
The term was used to describe the twelve chosen by Jesus as well as Barnabas and Paul.
[Which] when the apostles, [apostolos] Barnabas and Paul, heard [of], they rent their clothes, and ran in among the people, crying out, - Acts 14:14
I asked God in earnest prayer what my gift in the Spirit is (we all have at least one.) The reply was that I am an encourager - like Barnabas was to Paul and the new converts. He has confirmed this many times in my life as He puts me in positions to encourage my brothers and sisters in Him who may have become weary or weak kneed in the face of circumstances of life (the "weeds" such as facing death, sickness, depression, politics, peer pressure, bitterness, science.)
As to those who are gifted to be apostles, I suggest it is very important to remember that God and not man is the One who gives the gift. Moreover, anyone gifted as an apostle must remember this always - because a lack of humility will lead to ruin both for himself and those around him in the body of Christ ("get thee behind me, Satan" - Matt 16):
My main objection to Catholicism is that it goes beyond the words of God, teaching as commandments of God the doctrine of men. [Mark 7:7] But I have that same objection over all the others, Eastern Orthodox, Calvinism, Arminianism, Mormonism and so on. It is nothing personal.
Nor do I discourage my beloved brothers and sisters in Christ who are truly much more comfortable relying on the doctrines and traditions of their faithful religious leaders. We are all different gemstones in the foundation of the New Jerusalem (to repeat a favorite metaphor.)
Christ chose twelve very different apostles, accepted seven very different churches. We are looking at a seven-faceted diamond from different aspects, but it is the same diamond, the same Light.
I expect to see all of my family in heaven and you too, dear Mad Dawg!
Maranatha, Jesus!